Means for controlling the headspacing of grenade cartridges in a single-shot launcher

ABSTRACT

IN A GRENADE LAUNCHER OF THE TYPE IN WHICH THE BARREL IS PIVOTED IN THE RECEIVER FOR LATERAL SWINGING MOVEMENT BETWEEN OPEN AND CLOSED BREECH POSITIONS, THE LOCKING ACTUATION OF THE BARREL LOCK IS ALSO UTILIZED TO SEAT THE LOADED CARTRIDGE IN POSITIVE FIRING CONTACT WITH A FIXED BREECH FACE IN THE RECEIVER WHILE THE UNLOCKING ACTUATION OF THE BARREL LOCK IS UTILIZED TO COMPLETE THE COCKING OF A SPRING-BIASED EXTRACTOR AND SIMULTANEOUSLY FREE THE FIRED CARTRIDGE CASE IN THE FIRING CHAMBER FOR EXTRACTION THEREFROM BY THE COCKED EXTRACTOR.

Jan. 26, 19 7 1 R C. HOOVER NG THE HEADSPACING 0F GRENADE CARTRIDGES IN A SINGLE-SHOT LAUNCHER 3 Sheets-Sheet 2' Y MEANS FOR coNTRoLL'I I :E'Ig E.

Filed Feb. 4, 1969 INVENTOR Huber i L Hnuvar HQW -b MAM f K.

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Jan. 26, 1971 HOOVER MEANS FOR CQNTRO NG THE HEADSPACING 0F GRENADE CARTRIDGES IN A SINGLE-SHOT LAUNCHER Filed Feb. 4, 1969 3 Sheets-Sheet 3 E Iol 6 58 46 VI -x94 Hill 1 & 34 I08 H2 48 42 105/106 59 INVENTOR Ember i L Hoover BY 1 -01 49" M I W A1156- M,

ATTORNEYS United States Patent Ofifice 3,557,482 Patented Jan. 26, 1971 US. CI. 4212 Claims ABSTRACT OF THE DISCLOSURE In a grenade launcher of the type in which the barrel is pivoted in the receiver for lateral swinging movement between open and closed breech positions, the locking actuation of the barrel lock is also utilized to seat the loaded cartridge in positive firing contact with a fixed breech face in the receiver while the unlocking actuation of the barrel lock is utilized to complete the cocking of a spring-biased extractor and simultaneously free the fired cartridge case in the firing chamber for extractlon therefrom by the cocked extractor.

BACKGROUND OF THE INVENTION This invention relates to a grenade launcher capable of being attached to a rifle and is more particularly directed to means for controlling the position of the grenade cartridge in the firing chamber before and after discharge thereof.

Certain military rifles are now capable of launching cartridge type grenades at any point during the normal operation of the rifle without the necessity for any substantial change in the grip of the user or the position in which the rifle is being operated. This has been accomplished by attaching a separate grenade launchin unit to the rifle in a manner permitting rapid switching between rifle and launcher operation at the option of the user without any intervening adjustment or manipulation. However, since the launcher is generally attached to the underside of the rifle to avoid interfering with the use of the sights thereon, considerable difficulty has been encountered in manually loading grenade cartridges into the firing chamber without detracting from the rapidity with which the rifie can be returned to the type of firing operation which was halted to fire the grenades, especially where the user is on the ground in a prone firing position.

Such difliculty has been successfully eliminated in a recent design of a grenade launcher attachment in which the barrel is laterally pivoted about a fixed point in the receiver to fully expose the breech end of such barrel for the normal loading of a cartridge therein without the need for any lifting or tilting of the rifle. However, the arcnate path followed by the breech end face of the barrel during the pivotal movement thereof between the open cartridge loading and closed breech positions has introduced several additional complicating factors. For example, since the length of the cartridge case must be slightly smaller than the overall length of the firing chamber in order for the base of the cartridge to clear the fixed vertical breech surface in the receiver during the pivotal movement of the barrel into the closed breech position thereof, the resulting space between the breech face of the barrel and the breech surface in the receiver may be great enough to seriously detract from the required impact of the firing pin against the primer in the base of the chambered cartridge. Furthermore, even if the cartridge were properly positioned in the firing chamber at the conclusion of the.

closing pivotal movement of the barrel, there is no assurance that the chambered cartridge would remain in such position during the locking of the barrel. Then too, both the extractor and ejector must be arranged so they will not protrude into the firing chamber area during the opening and closing of the breech. In addition, since the discharge gases generated upon the firing of the cartridge expand the walls of the case into tight contact with the interior of the barrel, some means must be provided for loosening the fired cartridge case in the barrel immediately prior to the regular extraction therefrom.

OBJECT OF THE INVENTION Accordingly, it is a primary object of this invention to provide means for controlling the longitudinal position, both before and after firing, of a grendate cartridge in the firing chamber of a grenade launcher rifle attachment of the type wherein the barrel is laterally pivoted about a fixed point in the receiver to open and close the breech.

It is a further object of this invention to effect the aforesaid control of the grenade cartridge through the same means utilized to lock and unlock the barrel in the closed breech position thereof.

Another object of this invention is to provide cartridge control means, as aforesaid, which will bring the base of the grenade cartridge into positive contact with the fixed breech surface in the receiver and retain the cartridge in such position prior to the firing thereof.

Still another object of the present invention resides in the provision of cartridge control means, as aforesaid, which will act on the fired cartridge case in the barrel to overcome any tendency to stick therein after the pressure of the discharge gases has been dissipated.

An additional object of this invention is to provide cartridge control means, as aforesaid, wherein a combined ex tractor and ejector mechanism and a barrel locking structure cooperate in seating the unfired cartridge against the fixed breech closure surface in the receiver A final object of this invention is to provide cartridge control means, as aforesaid, which will readily engage with and disengage from the rim of the cartridge in the barrel during the closing and opening of the breech despite the change in the longitudinal orientation of the cartridge rim due to the arcuate path followed by the breech end of the barrel during the pivotal movement thereof.

SUMMARY OF THE INVENTION It has been found that the foregoing objects can be attained in a single shot grenade launcher of the type in which the barrel is pivoted in the receiver for lateral swinging movement between the open and closed breech positions thereof, if use is made of the slidable member in the receiver which is arranged to be longitudinally actuated into and out of locking engagement with the barrel. In order to actuate the slidable barrel lock, an eccentric cam is rotatably mounted in a suitable opening in the rear end of the lock and is provided with a lever arm projecting outwardly from the side of the receiver to serve as a manual operating handle. When the handle is retracted, the barrel lock is correspondingly advanced to unlock the barrel and when the handle is pivoted forwardly, the barrel lock is drawn to the rear into locking engagement with the barrel.

When thebarrel is unlocked, the slidable lock is positioned so that a transverse slot therein will engage with the rim of the grenade cartridge in the barrel as the latter is pivoted to close the breech. Thus, as the lock is actuated rearwardly to lock the barrel, the chambered cartridge is simultaneously drawn into positive seating contact with the fixed surface in the receiver which serves to close the breech. As the lock is actuated forwardly to unlock the barrel, the fired cartridge case is simultaneously pushed forwardly to break the seal produced by the firing expansion of such case in the barrel. Thus, as

the barrel is pivoted to open the breech, the fired case is free to be forced rearwardly out of the firing chamber in the barrel by a spring-biased extractor slidably mounted in the barrel to project from the breech end thereof. Since the extractor is positioned to engage in the annular groove in the cartridge in front of the rim thereon, the forward loosening movement imparted to the fired cartridge case also serves to increase the cocking action previously imparted to the extractor during the insertion of a grenade cartridge into the barrel.

BRIEF DESCRIPTION OF THE DRAWINGS The exact nature of the invention as well as other objects and advantages thereof will be readily apparent from consideration of the following specification relating to the annexed drawings wherein:

FIG. 1 is a side view of the launcher attachment suspended from the barrel of a small caliber rifle, the exterior of the launcher being almost entirely broken away to show the cross-sectional configuration and the relationship of the parts immediately after firing;

FIG. 2 is a fragmentary view similar to that of FIG. 1 but showing the parts after the barrel has been unlocked;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2 to show the relationship between the barrel lock and the extractor;

FIG. 4 is an enlarged cross-sectional view taken along line 44 in FIG. 3 to show the internal details of the extractor in the cocked position thereof prior to the opening of the breech;

FIG. 5 is a view similar to that of FIG. 4 but with the parts in the position assumed during the extraction of the fired cartridge case;

FIG. 6 is a perspective View of the barrel lock;

FIG. 7 is a cross-sectional view taken along line 77 in FIG. 2 on an enlarged scale to show the structure 'which provides the forward and rearward longitudinal movement of the barrel lock;

FIG. 8 is a perspective view of the entire launcher attachment minus the adapter, the barrel being shown pivoted to the open loading position thereof; and

FIG. 9 is an exploded view of the extractor assembly.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT As illustrated in FIG. 1, a mounting adapter 12 is secured to the receiver 14 of a grenade launcher attachment and is also fastened, as indicated at 16, to the receiver 18 of a conventional military rifle. Adapter 12 also includes a yoke 20 extending upwardly from the forward end thereof to surround barrel 22 of the rifle and engage therewith in a manner which will insure that barrel 24 of the launcher will be parallel to barrel 22 of the rifle.

A cylindrical housing 26 is secured within launcher receiver 14 and extends rearwardly therefrom, as indicated at 28, to provide support for a pivotal trigger 30. Slidably mounted in receiver 14 is a firing pin 32 arranged to protrude beyond the front face 34 of receiver 14 when released in a conventional manner by the pulling of trigger 30. As explained hereinafter, face 34 in receiver 14 cooperates with the breech end of barrel 24 to provide a breech closure surface therefor.

The upper portion of receiver 14 is forwardly extended beyond breech closure surface 34 to provide an arm 36 containing a vertical hole 38 in the forward end thereof for rotatable engagement with a mating pin 40 projecting upwardly from the top of barrel 24. The lower end of receiver 14 is similarly extended, but to a lesser distance, to provide an arm 42 which cooperates with arm 36 to support the breech end of barrel 24 for pivotal movement into and out of axial alignment with firing pin 32. Rearwardly of pivot pin 40, barrel 24 is provided with a rectangular section 44 on the top of which is an arcuate rib 46 and on the bott m of Which is a rib 48 of similar contour but of greater width. Ribs 46 and 48 are arranged to slidably fit in mating arcuate grooves 50 and 52 formed in the inner surfaces of arms 36 and 42 respectively. Thus, barrel 24 is mounted to receiver 14 for lateral pivotal movement between an open loading position as best shown in FIG. 8 and a closed breech position as best shown in FIGS. 1 and 2. Movement of barrel 24 beyond the open loading position thereof is halted by a stud 54 threadably secured in one of a pair of corresponding threaded recesses 55 located respectively adjacent the opposite sides of arm 42, as shown in FIG. 3, to project upwardly therefrom into a closed-end groove 56 centrally provided in the underside of arcuate rib 48. Movement of barrel 24 into the closed breech position thereof is halted by a lug 58 which, as shown in FIG. 8, is replaceably fixed to the side of receiver 14 to extend forwardly of the breech closure surface therein.

As best shown at 59 in FIG. 8, the lower portion of the breech end of barrel 24 is of rectangular configuration while the upper portion is arcuately formed, as indicated at 61, to blend into rectangular configuration 59. A rectangular cut-out area 63 is centrally provided at the top of the circular configuration 61 for a purpose to be explained. In addition, barrel 24 is longitudinally bored to receive cylindrical grenade cartridges in which the case portion 62 thereof terminates in an annular extractor groove 64 and a rearwardly adjacent rim 66 of larger diameter than case portion 62. The bore diameter of barrel 24 is slightly enlarged, as best shown at 68 in FIG. 1, to a point therein which cooperates with breech closure surface 34 in receiver 14 to form a firing chamher 70 at least longer than cartridge case 62. Thus, when a cartridge is manually inserted into the bore of barrel 24, the front edge of cartridge case 62 will be halted by restriction 68 as best shown in FIG. 2. In this position, extractor groove 64 and rim 66 of cartridge case 62 will project from the breech end of barrel 24 but not to an extent which will prevent cartridge case rim 66 from clearing the edge of breech closure surface 34 in receiver 14 as barrel 24 is pivoted to close the breech.

The locking and unlocking of barrel 24 in the closed breech position thereof is accomplished by a rectangular lock 72 slidably mounted in a corresponding slot 74 vertically provided in the top of receiver 14. Lock 72 includes a rearward body portion 73 and a forward portion 76 of reduced height which is arranged to extend through a mating passage 78 (FIG. 8) in rib 46 on the top of rectangular section 44 of barrel 24. A transverse channel 80 is cut into the underside of the reduced portion 76 of lock 72 and when such channel 80 is in alignment with the portions of rib 46 on each side of passage 78 therethrough, barrel 24 is free to pivot about pin 40 in receiver 14. When lock 72 is positiond so that channel 80 therein is out of alignment with the ends of rib 46 produced by passage 78 therethrough, pivotal movement of barrel 24 is blocked.

Immediately to the rear of forward portion 76 thereof, lock 72 is provided with a depending transverse tooth 82 of rectangular configuration and of slightly shorter vertical extent than rearward body portion 73 to provide a transverse slot 84 for the entry of rim 66 of cartridge case 62. The rearward wall of slot 84 is beveled at each end thereof, as indicated at 85 in FIG. 6, for a purpose to be explained hereinafter. In addition, the front face of tooth 82 is partially sloped, as shown at 86 in FIG. 2 to provide clearance for the forwardly inclined front wall 88 of annular groove 64 in cartridge case 62.

A rectanglar opening 92 is provided in the underside of body portion 73 of lock 72 and the opposite sidewalls of opening 92 are triangularly shaped to form bearing surfaces 94 for rotatably receiving an elliptically enlarged end 96 of a locking lever 98. As best shown in FIG. 7, the interior of receiver 14 includes a circular recess 103 arranged to freely accommodate elliptical end 96 of lever 98. A rectangular slot 99 with diverging side walls 101 is transversely located in each side of receiver 14 to intersect recess 103 and provide access for the forward and rearward movements of the handle end of lever 98. In view of the symmetrical configuration of slots 99 and recess 103, locking lever 98 can be readily relocated to project from the left hand side of receiver 14 in order to accommodate a left-handed shooter. Elliptical end 96 of lever 98 is provided with a square hole 100 therethrough disposed to be offset from the true center of end 96 and engageable with a mating pin 102 projecting upwardly from the upper end of a cylindrical shaft 104 mounted in receiver 14. Thus, locking lever 98 is mounted for rotation about a vertical axis. Due to the offset location of hole 100 in elliptical end 96, movement of lever 98 forwardly in slot 99 will provide an eccentric rearward thrust on lock 72 which will impart corresponding longitudinal movement thereto. Retraction of lever 98 in slot 99 will similarly impart forward movement to lock 72.

An extractor assembly 105 includes a hollow cylindrical body 106 which is slidably mounted in a longitudinal hole 108 located in the breech end of barrel 24 at the lower right-hand corner thereof, as seen in FIG. 8. Hole 108 is of shorter length than extractor body 106 so that the rear end thereof projects from barrel 24. Extractor body 106 is longitudinally split along the upper periphery thereof, as best indicated at 110 in FIG. 9, to provide for the entry of the upper end of a pawl 112. The lower end of pawl 112 is pivotally secured in a corresponding slot 114 in the lower periphery of extractor body 106 by a transverse pin 116. The pivot point and the height of pawl 112 are designed so that the upper rear corner thereof will project into the annular groove 64 at the rear end of the cartridge in barrel 24 for engagement wtih rim 66. Pawl 112 is provided with a divergent front edge 118 while the vertical wall of slot 114 is suitably sloped, as indicated at 120 in FIG. 5, to provide a stop surface for the counterclockwise movement of pawl 112. The upper portion of pawl edge 118 is arranged to receive the thrust of an enlarged head 122 at the rear end of a plunger 124. A coil spring 126 surrounds plunger 124 with one end of spring in abutment with the front end wall of extractor hole 108 and the other end seated against the front face of plunger head 122. The rear face of plunger head 122 is forwardly and downwardly sloped to leave a realtively narrow contact surface 128 at the upper end thereof. As a result, plunger 124 will contact pawl 112 so as to provide a maximum of leverage thereon. A groove 130 is transversely provided in the underside of extractor body 106 to cooperate with a transverse pin 132 fixedly secured in the breech end of barrel 24 for stopping the forward end and rearward travel of extractor assembly 105.

Although the drawings show barrel 24 mounted in receiver 14 to permit the loading of cartridges therein from the right-hand side of the launcher attachment, it should be understood that loading can also be accomplished from the left-hand side merely by the simple changeover of a few components. Barrel 24 is provided with a second extractor-receiving hole 108 in the left-hand corner of the breech end thereof. Consequently, extractor assembly 105 can be changed from right-hand to left-hand operation once transverse pin 132 is removed from the breech end of barrel 24. The changeover is then completed by changing threaded stud 54 to the left-hand end of groove 56 in arcuate rib 48 and changing stop lug 58 to the righthand side of receiver 14.

If the grenade launcher contains a chambered cartridge, operation thereof is initiated simply by pulling trigger 30. Once the cartridge is fired, lever 98 can be pulled to the rear until halted by contact with the sloping rear end wall 101 of rectangular slot 99 as best shown in FIG. 7. During this pivotal movement of lever 98, the elliptical contour of the enlarged end 96 and the offset location of the point about which end 96 is arranged to rotate cooperate to impart forward movement to lock 72 which brings transverse channel 80 therein into unlocking alignment with passage 78 in arcuate rib 46 on the top of the breech end of barrel 24. Thereupon, barrel 24 is free to be manually pivoted to the open cartridge loading position shown in FIG. 8.

As lock 72 is moved forwardly in receiver 14, the rear wall of transverse slot 84 moves into cut-out area 63 to contact the base of rim 66 on the fired cartridge case 62 and advances such case at least into the bore of barrel 24 thereby breaking the sealing contact between the walls of the fired case and the interior bore surface of barrel 24. The forward movement of the fired cartridge case 62 also pivots extractor pawl 112 against plunger head 122 to increase the cocking compression of spring 126. Once barrel 24 is unlocked, it can be manuall pivoted to the loading position shown in FIG. 8. As soon as the base of the fired case 62 clears breech closure surface 34 in receiver 14, the thrust of compressed spring 126 actuates plunger 124 to pivot pawl 112 in the counterclockwise direction with sufficient force to initiate extraction of the fired cartridge case 62 from the bore of barrel 24. The pivotal movement of pawl 112 is halted as the lower portion of edge 118 thereon impacts against the sloped end wall 120 in the rear end of slot 114. However, the continuing action of spring 126 urges the entire extractor assembly 105 rearwardly to complete the required ejection of fired case 62.

In order to load a cartridge into barrel 24, it is merely necessary to manually insert such cartridge therein and push it forwardly until the forward edge of case 62 contacts bore restriction 68. As the cartridge is pushed forwardly, rim 66 thereon contacts the upper portion of pawl 112 and imparts clockwise pivotal movement hereto. As a result, plunger 124 is driven forwardly to compress spring 126 and thereby provide the energy required to effect the subsequent extraction and ejection stroke of extractor assembly 105. While the cartridge is manually held in barrel 24, the latter is pivoted to bring such cartridge into receiver 14 in axial alignment with firing pin 32 therein. During this closure of the breech, beveled surface 85 cams rim 66 of cartridge 60 into transverse slot 84 in lock 72.

Thus, as lever 98 is pushed forwardly in receiver 14, lock 72 is actuated rearwardly to withdraw transverse channel therein out of alignment with passage 78 in rib 46 thereby blocking any pivotal movement of barrel 24. As lock 72 is being actuated to the rear, depending tooth 82 thereon contacts rim 66 on cartridge case 62 and thereby pulls the base of the cartridge into positive contact with breech closure surface 34 of receiver 14. Thus, the cartridge will be seated in firing chamber 70 in the position required for proper impact by firing pin 32 and will be retained therein as long as lock 72 is in the barrel locking position. The retention of the cartridge in the proper firing position thereof is assisted by the rearward thrust of plunger 124 against pawl 112 which is, in turn, forced against cartridge case rim 66 at a point diametrically opposite the engagement thereof by depending tooth 82 on lock 72.

As a result of the foregoing structure, a single shot launcher can be provided with a laterally pivotal barrel which can be manually loaded and unloaded without requiring any tilting or lifting of the rifle to which the launcher is attached. Accordingly, when the launching of grenade cartridges is no longer desired, the firing of the rifle can be immediately resumed without the necessity for any extensive repositioning thereof. This is especially desirable when the operator of the rifle is firing from a prone position and the tactical situation is such that exposure to hostile fire must be kept to an absolute minimum. An important advantage of the present invention resides in the fact that the use of the existing barrel locking mechanism for properly positioning the loaded cartridge in the firing chamber prior to firing and for subsequently loosening the fired cartridge case therein does not increase the number of components or require separate adjustments to the grenade launcher. Thus, the problems heretofore encountered in the use of a laterally pivotable barrel are fully overcome in a simple, positive and economical manner.

Although the present invention is explained in accordance with the preferred embodiment shown and described herein, it will also become obvious to persons skilled in the art that other forms thereof, as well as changes in the particular form described, are possible within the spirit and scope of the present invention. Therefore, it is desired that the present invention shall not be limited except insofar as it is made necessary by the prior art and by the spirit of the appended claims.

I claim:

1. In a grenade launcher rifle attachment having a fixed breech closure surface, a barrel pivotally mounted at a fixed point forwardly of the breech end thereof for lateral movement between an open cartridge loading position wherein the breech end is exposed for the insertion therein of a cartridge with a rimmed case and a closed firing position wherein the breech end of the barrel cooperates with the fixed breech closure surface to complete a firing chamber, and a barrel lock slidably disposed for longitudinal movement into and out of locking engagement with the barrel, the improvement therein of,

means on the barrel lock for engaging the rim of the cartridge in the firing chamber whereby the locking actuation of the barrel lock simultaneously positions the chambered cartridge into positive contact with the fixed breech closure surface and whereby the unlocking actuation of the barrel lock simultaneously loosens the fired cartridge case in the firing chamber.

2. The combination defined in claim 1 wherein said means on the barrel lock for engaging the rim of the cartridge in the firing chamber comprises:

a tooth depending from the underside of the barrel lock and spaced forwardly of a forwardly facing shoulder therein to define a transverse slot for receiving the rim of the cartridge in the barrel, and

a cam surface at one end of said transverse slot for directing the cartridge rim therein during the pivotal movement of the barrel into the closed firing position thereof.

3. The combination defined in claim 1 including a rearwardly biased extractor slidably disposed in the breech end of the barrel for contact with the front face of the rim on the chambered cartridge whereby the fired case thereof is automatically extracted and ejected from the barrel during the pivotal movement thereof toward the open cartridge loading position.

4. In a grenade launcher rifle attachment having a receiver with a fixed vertical breech closure surface, and a barrel pivotally mounted in the receiver for lateral movement about a fixed point forwardly of the breech end thereof between an open loading position wherein the breech end thereof is exposed for the insertion of a cartridge with a case terminating in a diametrically enlarged rim and a closed breech position wherein the breech end of the barrel cooperates with the breech closure surface in the receiver to complete a firing chamber of slightly greater length than the cartridge case, the combination of:

a barrel lock slidably disposed in the receiver for longitudinal movement into and out of engagement with the barrel for blocking the pivotal movement thereof,

said lock having a reduced portion forming a forwardly facing shoulder on the underside thereof, a tooth depending from the underside of said barrel lock and spaced forwardly of said shoulder thereon to define a transverse slot for receiving the rim of the cartridge in the barrel during the pivotal movement thereof toward the closed breech position, and

a lever pivotally mounted in the receiver for actuating said barrel lock in one direction to block the barrel against pivotal movement and simultaneously position the cartridge in the firing chamber into positive contact with the fixed breech closure surface in the receiver and for actuating said barrel lock in the opposite direction, after the chambered cartridge is fired, to free the barrel for pivotal movement and simultaneously loosen the fired cartridge case in the firing chamber for subsequent extraction and ejection from the barrel.

5. The combination defined in claim 4 including an extractor slidably mounted in the breech end of the barrel, and spring means for normally biasing said extractor into contact with the front face of the rim on the cartridge in the firing chamber whereby the loosened fired cartridge case is automatically extracted and ejected from the barrel when the breech end of the barrel clears the fixed breech closure surface in the receiver during the pivotal movement of the barrel to the open cartridge loading position thereof.

6. The combination defined in claim 4 wherein said barrel lock includes a transverse opening in the rear end thereof having opposed bearing surfaces therein and said lever includes an enlarged elliptical end rotatably seated between said bearing surfaces for actuating said barrel lock forwardly and rearwardly in response to the pivotal movement of said lever.

7. The combination defined in claim 4 wherein said transverse slot in the underside of said barrel lock includes a cam surface for ensuring the entry therein of the rim on the cartridge in the barrel irrespective of the longitudinal position of the rim relative to the breech end of the barrel during the pivotal movement thereof toward the closed position.

8. In a grenade launcher rifle attachment having a receiver with a fixed vertical breech closure surface, and a barrel pivotally mounted in the receiver for lateral movement about a fixed point forwardly of the breech end thereof between an open loading position wherein the breech end of the barrel is exposed for the insertion of a cartridge with a case terminating in a diametrically enlarged rim and a closed breech position wherein the breech end of the barrel cooperates with the breech closure surface in the receiver to complete a firing chamber of slightly greater length than the cartridge case, the combination of:

a barrel lock slidably disposed in the receiver for longitudinal movement into and out of engagement with the barrel for respectively blocking and unblocking the pivotal movement thereof, said lock having a transverse slot in the underside thereof for receiving the rim of the cartridge in the barrel during the pivotal movement thereof toward the closed breech position,

a lever pivotally mounted in the receiver in camming engagement with said barrel lock for actuating the latter into and out of position to block pivotal movement of the barrel whereby the locking actuation of said barrel lock positions the cartridge in the firing chamber against the fixed breech closure surface in the receiver to eliminate any clearance therebetween and the unlocking actuation of said barrel lock, following the firing of the chambered cartridge, loosens the fired case in the firing chamber,

an extractor slidably mounted in the breech end of the barrel in position to contact the front face of the rim on the cartridge in the firing chamber, and

spring means biasing said extractor rearwardly to extract and eject the fired and loosened case from the barrel as soon as the rear end of the case clears the breech closure surface in the receiver during the pivotal movement of the barrel to the open cartridge loading position thereof.

9. The combination defined in claim 8 wherein the underside of said barrel lock includes a transverse opening in the rear end thereof having opposed bearing surfaces,

said lever includes an enlarged elliptical end seated bea spring seated in the breech end of the barrel to bear tween said bearing surfaces and in contact therewith, and against said plunger and impart counterclockwise the receiver includes a vertically disposed rotatable shaft pivotal movement to said pawl for extracting and aving the upper end thereof in fixed engagement with ejecting the fired cartridge case from the barrel and said elliptical lever end at a point offset from the true 5 for assisting said barrel lock in providing positive center thereof whereby pivotal movement of said lever contact between the rear end of the chambered carcams said breech lock into and out of locking engagetridge and the fixed breech closure surface in the ment with the barrel. receiver.

10. The combination defined in claim 8 wherein said References Cited extractor comprises:

a hollow body slidably disposed in the breech end of 10 UNITED STATES PATENTS the barrel to project rearwardly therefrom, 2577335 12/1951 Lambeft 4212 ,332,162 7/1967 Martwlck et al. 421(F) a stop pin fixed 1n the barrel to llmit the slidable move- 3 ment of said extractor body, a pawl pivoted in the rear end of said extractor body BENJAMIN BORCHELT Pnmary Examiner in position to contact the front face of the rim on C. T. JORDAN, Assistant Examiner the cartridge in the 'barrel at a point diametrically opposed to the contact of said barrel lock therewith, i.

a plunger slidably disposed in the interior of said ex- 20 tractor body, and 

